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Solution of a Time-Space Tempered Fractional Diffusion-Wave Equation and its Theoretical Aspects

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Acta Mathematicae Applicatae Sinica 2025年第1期41卷 1-26页

作者： Pratibha VERMA Surabhi TIWARI Department of Mathematics Indian Institute of Technology JodhpurJodhpur-342030RajasthanIndia Department of Mathematics Motilal Nehru National Institute of Technology AllahabadPrayagraj-211004Uttar PradeshIndia

This article proves the existence and uniqueness conditions of the solution of two-dimensional time-space tempered fractional diffusion-wave equation. We find analytical solution of the equation via the two-step Adomian decomposition method(TSADM). The existence result is obtained with the help of some fixed point theorems, while the uniqueness of the solution is a consequence of the Banach contraction ***, we study the stability via the Ulam-Hyers stability for the considered problem. The existing techniques use numerical algorithms for solving the two-dimensional time-space tempered fractional diffusionwave equation, and thus, the results obtained from them are the approximate solution of the problem with high computational and time complexity. In comparison, our proposed method eliminates all the difficulties arising from numerical methods and gives an analytical solution with a straightforward process in just one iteration.

关键词： Caputo fractional derivative two-step Adomian decomposition method time-space tempered fractional di usion-wave equation Riesz derivative Ulam-Hyers stability xed point theorem

Multifunctional Nacre‑Like Nanocomposite Papers for Electromagnetic Interference Shielding via Heterocyclic Aramid/MXene Template‑Assisted In‑Situ Polypyrrole Assembly

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Nano-Micro Letters 2025年第3期17卷 37-54页

作者： Jinhua Xiong Xu Zhao Zonglin Liu He Chen Qian Yan Huanxin Lian Yunxiang Chen Qingyu Peng Xiaodong He national Key Laboratory of Science and technology On Advanced Composites in Special Environments Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080People’s Republic of China

Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic *** this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.

关键词： MXene Remarkable mechanical properties Heterocyclic aramid Electromagnetic interference shielding Polypyrrole Multifunctionality

Impulsive thrust strategy for orbital pursuit-evasion games based on impulse-like constraint

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Chinese Journal of Aeronautics 2025年第1期38卷 520-536页

作者： Hongbo WANG Yao ZHANG Hao LIU Kunpeng ZHANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China national Key Laboratory of Space Intelligent Control Beijing Institute of Control EngineeringBeijing 100094China

This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust *** strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous ***,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust ***,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this *** learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal ***,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like ***,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust *** examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is *** effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.

关键词： Orbital pursuit-evasion game Differential game Impulsive thrust Deep learning Shooting method

Four-wave mixing Bragg scattering for small frequency shift from silicon coupled microrings

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Chinese Physics B 2025年第1期34卷 351-355页

作者： Chang Zhao Chao Wu Pingyu Zhu Yuxing Du Yan Wang Miaomiao Yu Kaikai Zhang Ping Xu institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China

Frequency conversion is pivotal in nonlinear optics and quantum optics for manipulating and translating light signals across different wavelength *** frequency conversion between two light beams with a small frequency interval is a central *** this work,we design a pair of coupled silicon microrings wherein coupled-induced modesplitting exists to achieve a small frequency shift by the process of four-wave mixing Bragg *** an example,the signal can be up or down converted to the idler which is 15.5 GHz spaced when two pumps align with another pair of split *** results unveil the potential of coupled microring resonators for small interval frequency conversion in a high-fidelity,all-optical,and signal processing quantum frequency interface.

关键词： four-wave mixing Bragg scattering silicon coupled microrings

HfC–HfO2 modified high/superhigh temperature thermal protection coating for superior hot corrosion resistance and antioxidation performance

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Journal of Advanced Ceramics 2025年第1期14卷 177-191页

作者： Zhiyun Ye Shuqi Wang Shuang Yu Xinrui Zhao Yongchun Zou Guoliang Chen Lei Wen Lina Zhao Guangxi Zhang Yaming Wang Jiahu Ouyang Dechang Jia Yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001China institute for Advanced Ceramics Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing technology Harbin Institute of TechnologyHarbin 150001China national Center for Materials Service Safety University of Science and Technology BeijingBeijing 100083China Xi’an Aerospace Composites Research institute Academy of Aerospace Propulsion TechnologyXi’an 710025China

With advances in the thrust-weight ratio,the service temperature of gas turbine engines even exceeds 1500℃,which is urgent for the development of high/superhigh-temperature thermal protection systems(TPSs)for long-term *** alloys are increasingly viewed as promising structural materials for high-temperature applications because of their superior high-temperature mechanical strength,but the“pest”catastrophic oxidation greatly restricts their further *** this study,a HfC–HfO2-modified silicide coating was prepared via an innovative method of halide-activated pack cementation(HAPC)combined with liquid-plasma-assisted particle deposition and sintering of niobium alloys,resulting in a composite coating with excellent hot corrosion resistance and high-temperature oxidation *** modified multilayer coating is characterized by the synergistic combination of a dense NbSi2 inner layer and a HfC–HfO2 porous outer layer,resulting in a significant improvement in high-temperature performance compared with that of the single NbSi2 *** corrosion gain of the composite coating is only 13.94 mg·cm−2 after a corrosion time of 200 h at 900℃,and an intact oxide scale surface is observed after oxidation at 1500℃for 500 *** improvement is attributed to the formation of a robust Hf-rich skeleton provided by the deposited HfC–HfO2 layer,which can accelerate the formation of a highly stable corroded layer/oxide *** addition,multiple stress release mechanisms of the composite coating at high temperatures also provide substantial contributions to long-term *** these merits make HfC–HfO2-modified composite coatings on niobium alloys competitive for the development of high/superhigh-temperature thermal protection systems for long-term service.

关键词： thermal protection coating niobium alloys hot corrosion resistance high-temperature oxidation resistance stress releasemechanism

Pentago SnW: An Improved Spray and Wait Protocol for Delay Tolerant Wireless Sensor Networks

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China Communications 2025年第03期 104-114页

作者： Idris Afzal Shah Mushtaq Ahmed Raghavendra Singh Department of Computer Science and Engineering Malaviya National Institute of Technology

Delay tolerant wireless sensor networks(DTWSN) is a class of wireless network that finds its deployment in those application scenarios which demand for high packet delivery ratio while maintaining minimal overhead in order to prolong network lifetime; owing to resource-constrained nature of *** fundamental requirement of any network is routing a packet from its source to destination. Performance of a routing algorithm depends on the number of network parameters utilized by that routing protocol. In the recent years, various routing protocol has been developed for the delay tolerant networks(DTN).A routing protocol known as spray and wait(SnW)is one of the most widely used routing algorithms for DTN. In this paper, we study the SnW routing protocol and propose a modified version of it referred to as Pentago SnW which is based on pentagonal number series. Comparison to binary SnW shows promising results through simulation using real-life scenarios of cars and pedestrians randomly moving on a map.

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Output Consensus of Heterogeneous Linear MASs via Adaptive Event-Triggered Feedback Combination Control

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 285-287页

作者： Shuo Yuan Chengpu Yu Jian Sun the School of Automation Beijing Institute of Technology the Beijing institute of technology Chongqing Innovation Center

Dear Editor,This letter studies output consensus problem of heterogeneous linear multiagent systems over directed graphs. A novel adaptive dynamic event-triggered controller is presented based only on the feedback combination of the agent's own state and neighbors' output,which can achieve exponential output consensus through intermittent communication. The controller is obtained by solving two linear matrix equations, and Zeno behavior is excluded.

关键词： Directed graphs

Particle Swarm Optimization Based Support Vector Regression for Blind Image Restoration

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Journal of Computer Science & technology 2012年第5期27卷 989-995页

作者： Ratnakar Dash Pankaj Kumar Sa Banshidhar Majhi Computer Science and Engineering Department National Institute of Technology RourkelaRourkela 769008India

This paper presents a swarm intelligence based parameter optimization of the support vector machine （SVM） for blind image restoration. In this work, SVM is used to solve a regression problem. Support vector regression （SVR） has been utilized to obtain a true mapping of images from the observed noisy blurred images. The parameters of SVR are optimized through particle swarm optimization （PSO） technique. The restoration error function has been utilized as the fitness function for PSO. The suggested scheme tries to adapt the SVM parameters depending on the type of blur and noise strength and the experimental results validate its effectiveness. The results show that the parameter optimization of the SVR model gives better performance than conventional SVR model as well as other competent schemes for blind image restoration.

关键词： image restoration support vector regression particle swarm optimization

Insights into structural and spectroscopic characterization of Sm^(3+)doped orange rich red emitting CsMgPO_(4)phosphors

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Journal of Rare Earths 2022年第12期40卷 1837-1848,I0001页

作者： M.K.Pradhan S.Dash Department of Physics and Astronomy National Institute of Technology RourkelaRourkela769008OdishaIndia

In the present study,Sm^(3+)activated inorganic orthophosphate CsMgPO_(4)(CSMP)phosphors were prepared by adopting a solid-state reaction *** structural phase purity and morphological features were studied by X-ray powder diffraction(XRD)and scanning electron microscopy(SEM),*** molecular structure and vibrational modes were substantiated with the Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy *** optical bandgap of the host and Sm^(3+)doped phosphors was deduced from the diffused reflectance(DR)spectra with a typical value of 5.72 eV and a small variation is observed with increasing concentrations.A systematic study of photoluminescence(PL)properties of Sm^(3+)doped CSMP phosphors was carried *** the room temperature excitation and emission spectra,it is found that the phosphor emits in the orange rich red light under the suitable excitation of 402 nm in the UV region and concentration quenching occurs at x=0.02 doping *** emission peaks observed at around 562,598 and 644 nm confirm the characteristic Sm^(3+)4 f-4 f *** temperature-dependent photoluminescence(TD-PL)of the x=0.02(optimum doping)is recorded from 30 to 210℃,showing good thermal stability even at 150℃.The thermal quenching mechanisms are discussed based on the configuration coordinate model of excitation and *** prepared phosphors are found to exhibit near thermal stability compared to the commercially available red *** decay time and quantum efficiency were *** colour coordinates are found to lie in the orangish-red region of the colour *** the prepared phosphors CSMP:x Sm^(3+)can be useful as a red component in designing UV excitable chip-based phosphor-converted white LED applications.

关键词： Charge compensation Red phosphors Thermal stability Configuration coordinate model Luminescence Rare earths